///*
// * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
// * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
// *
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// */
//
//package com.atguigu.src7;
//
//import java.util.*;
//
///**
// * Resizable-array implementation of the <tt>List</tt> interface.  Implements
// * all optional list operations, and permits all elements, including
// * <tt>null</tt>.  In addition to implementing the <tt>List</tt> interface,
// * this class provides methods to manipulate the size of the array that is
// * used internally to store the list.  (This class is roughly equivalent to
// * <tt>Vector</tt>, except that it is unsynchronized.)
// *
// * <p>The <tt>size</tt>, <tt>isEmpty</tt>, <tt>get</tt>, <tt>set</tt>,
// * <tt>iterator</tt>, and <tt>listIterator</tt> operations run in constant
// * time.  The <tt>add</tt> operation runs in <i>amortized constant time</i>,
// * that is, adding n elements requires O(n) time.  All of the other operations
// * run in linear time (roughly speaking).  The constant factor is low compared
// * to that for the <tt>LinkedList</tt> implementation.
// *
// * <p>Each <tt>ArrayList</tt> instance has a <i>capacity</i>.  The capacity is
// * the size of the array used to store the elements in the list.  It is always
// * at least as large as the list size.  As elements are added to an ArrayList,
// * its capacity grows automatically.  The details of the growth policy are not
// * specified beyond the fact that adding an element has constant amortized
// * time cost.
// *
// * <p>An application can increase the capacity of an <tt>ArrayList</tt> instance
// * before adding a large number of elements using the <tt>ensureCapacity</tt>
// * operation.  This may reduce the amount of incremental reallocation.
// *
// * <p><strong>Note that this implementation is not synchronized.</strong>
// * If multiple threads access an <tt>ArrayList</tt> instance concurrently,
// * and at least one of the threads modifies the list structurally, it
// * <i>must</i> be synchronized externally.  (A structural modification is
// * any operation that adds or deletes one or more elements, or explicitly
// * resizes the backing array; merely setting the value of an element is not
// * a structural modification.)  This is typically accomplished by
// * synchronizing on some object that naturally encapsulates the list.
// *
// * If no such object exists, the list should be "wrapped" using the
// * {@link Collections#synchronizedList Collections.synchronizedList}
// * method.  This is best done at creation time, to prevent accidental
// * unsynchronized access to the list:<pre>
// *   List list = Collections.synchronizedList(new ArrayList(...));</pre>
// *
// * <p><a name="fail-fast"/>
// * The iterators returned by this class's {@link #iterator() iterator} and
// * {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>:
// * if the list is structurally modified at any time after the iterator is
// * created, in any way except through the iterator's own
// * {@link ListIterator#remove() remove} or
// * {@link ListIterator#add(Object) add} methods, the iterator will throw a
// * {@link ConcurrentModificationException}.  Thus, in the face of
// * concurrent modification, the iterator fails quickly and cleanly, rather
// * than risking arbitrary, non-deterministic behavior at an undetermined
// * time in the future.
// *
// * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
// * as it is, generally speaking, impossible to make any hard guarantees in the
// * presence of unsynchronized concurrent modification.  Fail-fast iterators
// * throw {@code ConcurrentModificationException} on a best-effort basis.
// * Therefore, it would be wrong to write a program that depended on this
// * exception for its correctness:  <i>the fail-fast behavior of iterators
// * should be used only to detect bugs.</i>
// *
// * <p>This class is a member of the
// * <a href="{@docRoot}/../technotes/guides/collections/index.html">
// * Java Collections Framework</a>.
// *
// * @author  Josh Bloch
// * @author  Neal Gafter
// * @see     Collection
// * @see     List
// * @see     LinkedList
// * @see     Vector
// * @since   1.2
// */
//
//public class ArrayList<E> extends AbstractList<E>
//        implements List<E>, RandomAccess, Cloneable, java.io.Serializable
//{
//    private static final long serialVersionUID = 8683452581122892189L;
//
//    /**
//     * The array buffer into which the elements of the ArrayList are stored.
//     * The capacity of the ArrayList is the length of this array buffer.
//     */
//    private transient Object[] elementData;
//
//    /**
//     * The size of the ArrayList (the number of elements it contains).
//     *
//     * @serial
//     */
//    private int size;
//
//    /**
//     * Constructs an empty list with the specified initial capacity.
//     *
//     * @param  initialCapacity  the initial capacity of the list
//     * @throws IllegalArgumentException if the specified initial capacity
//     *         is negative
//     */
//    public ArrayList(int initialCapacity) {
//        super();
//        if (initialCapacity < 0)
//            throw new IllegalArgumentException("Illegal Capacity: "+
//                                               initialCapacity);
//        this.elementData = new Object[initialCapacity];
//    }
//
//    /**
//     * Constructs an empty list with an initial capacity of ten.
//     */
//    public ArrayList() {
//        this(10);
//    }
//
//    /**
//     * Constructs a list containing the elements of the specified
//     * collection, in the order they are returned by the collection's
//     * iterator.
//     *
//     * @param c the collection whose elements are to be placed into this list
//     * @throws NullPointerException if the specified collection is null
//     */
//    public ArrayList(Collection<? extends E> c) {
//        elementData = c.toArray();
//        size = elementData.length;
//        // c.toArray might (incorrectly) not return Object[] (see 6260652)
//        if (elementData.getClass() != Object[].class)
//            elementData = Arrays.copyOf(elementData, size, Object[].class);
//    }
//
//    /**
//     * Trims the capacity of this <tt>ArrayList</tt> instance to be the
//     * list's current size.  An application can use this operation to minimize
//     * the storage of an <tt>ArrayList</tt> instance.
//     */
//    public void trimToSize() {
//        modCount++;
//        int oldCapacity = elementData.length;
//        if (size < oldCapacity) {
//            elementData = Arrays.copyOf(elementData, size);
//        }
//    }
//
//    /**
//     * Increases the capacity of this <tt>ArrayList</tt> instance, if
//     * necessary, to ensure that it can hold at least the number of elements
//     * specified by the minimum capacity argument.
//     *
//     * @param   minCapacity   the desired minimum capacity
//     */
//    public void ensureCapacity(int minCapacity) {
//        if (minCapacity > 0)
//            ensureCapacityInternal(minCapacity);
//    }
//
//    private void ensureCapacityInternal(int minCapacity) {
//        modCount++;
//        // overflow-conscious code
//        if (minCapacity - elementData.length > 0)
//            grow(minCapacity);
//    }
//
//    /**
//     * The maximum size of array to allocate.
//     * Some VMs reserve some header words in an array.
//     * Attempts to allocate larger arrays may result in
//     * OutOfMemoryError: Requested array size exceeds VM limit
//     */
//    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
//
//    /**
//     * Increases the capacity to ensure that it can hold at least the
//     * number of elements specified by the minimum capacity argument.
//     *
//     * @param minCapacity the desired minimum capacity
//     */
//    private void grow(int minCapacity) {
//        // overflow-conscious code
//        int oldCapacity = elementData.length;
//        int newCapacity = oldCapacity + (oldCapacity >> 1);
//        if (newCapacity - minCapacity < 0)
//            newCapacity = minCapacity;
//        if (newCapacity - MAX_ARRAY_SIZE > 0)
//            newCapacity = hugeCapacity(minCapacity);
//        // minCapacity is usually close to size, so this is a win:
//        elementData = Arrays.copyOf(elementData, newCapacity);
//    }
//
//    private static int hugeCapacity(int minCapacity) {
//        if (minCapacity < 0) // overflow
//            throw new OutOfMemoryError();
//        return (minCapacity > MAX_ARRAY_SIZE) ?
//            Integer.MAX_VALUE :
//            MAX_ARRAY_SIZE;
//    }
//
//    /**
//     * Returns the number of elements in this list.
//     *
//     * @return the number of elements in this list
//     */
//    public int size() {
//        return size;
//    }
//
//    /**
//     * Returns <tt>true</tt> if this list contains no elements.
//     *
//     * @return <tt>true</tt> if this list contains no elements
//     */
//    public boolean isEmpty() {
//        return size == 0;
//    }
//
//    /**
//     * Returns <tt>true</tt> if this list contains the specified element.
//     * More formally, returns <tt>true</tt> if and only if this list contains
//     * at least one element <tt>e</tt> such that
//     * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
//     *
//     * @param o element whose presence in this list is to be tested
//     * @return <tt>true</tt> if this list contains the specified element
//     */
//    public boolean contains(Object o) {
//        return indexOf(o) >= 0;
//    }
//
//    /**
//     * Returns the index of the first occurrence of the specified element
//     * in this list, or -1 if this list does not contain the element.
//     * More formally, returns the lowest index <tt>i</tt> such that
//     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
//     * or -1 if there is no such index.
//     */
//    public int indexOf(Object o) {
//        if (o == null) {
//            for (int i = 0; i < size; i++)
//                if (elementData[i]==null)
//                    return i;
//        } else {
//            for (int i = 0; i < size; i++)
//                if (o.equals(elementData[i]))
//                    return i;
//        }
//        return -1;
//    }
//
//    /**
//     * Returns the index of the last occurrence of the specified element
//     * in this list, or -1 if this list does not contain the element.
//     * More formally, returns the highest index <tt>i</tt> such that
//     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
//     * or -1 if there is no such index.
//     */
//    public int lastIndexOf(Object o) {
//        if (o == null) {
//            for (int i = size-1; i >= 0; i--)
//                if (elementData[i]==null)
//                    return i;
//        } else {
//            for (int i = size-1; i >= 0; i--)
//                if (o.equals(elementData[i]))
//                    return i;
//        }
//        return -1;
//    }
//
//    /**
//     * Returns a shallow copy of this <tt>ArrayList</tt> instance.  (The
//     * elements themselves are not copied.)
//     *
//     * @return a clone of this <tt>ArrayList</tt> instance
//     */
//    public Object clone() {
//        try {
//            @SuppressWarnings("unchecked")
//                ArrayList<E> v = (ArrayList<E>) super.clone();
//            v.elementData = Arrays.copyOf(elementData, size);
//            v.modCount = 0;
//            return v;
//        } catch (CloneNotSupportedException e) {
//            // this shouldn't happen, since we are Cloneable
//            throw new InternalError();
//        }
//    }
//
//    /**
//     * Returns an array containing all of the elements in this list
//     * in proper sequence (from first to last element).
//     *
//     * <p>The returned array will be "safe" in that no references to it are
//     * maintained by this list.  (In other words, this method must allocate
//     * a new array).  The caller is thus free to modify the returned array.
//     *
//     * <p>This method acts as bridge between array-based and collection-based
//     * APIs.
//     *
//     * @return an array containing all of the elements in this list in
//     *         proper sequence
//     */
//    public Object[] toArray() {
//        return Arrays.copyOf(elementData, size);
//    }
//
//    /**
//     * Returns an array containing all of the elements in this list in proper
//     * sequence (from first to last element); the runtime type of the returned
//     * array is that of the specified array.  If the list fits in the
//     * specified array, it is returned therein.  Otherwise, a new array is
//     * allocated with the runtime type of the specified array and the size of
//     * this list.
//     *
//     * <p>If the list fits in the specified array with room to spare
//     * (i.e., the array has more elements than the list), the element in
//     * the array immediately following the end of the collection is set to
//     * <tt>null</tt>.  (This is useful in determining the length of the
//     * list <i>only</i> if the caller knows that the list does not contain
//     * any null elements.)
//     *
//     * @param a the array into which the elements of the list are to
//     *          be stored, if it is big enough; otherwise, a new array of the
//     *          same runtime type is allocated for this purpose.
//     * @return an array containing the elements of the list
//     * @throws ArrayStoreException if the runtime type of the specified array
//     *         is not a supertype of the runtime type of every element in
//     *         this list
//     * @throws NullPointerException if the specified array is null
//     */
//    @SuppressWarnings("unchecked")
//    public <T> T[] toArray(T[] a) {
//        if (a.length < size)
//            // Make a new array of a's runtime type, but my contents:
//            return (T[]) Arrays.copyOf(elementData, size, a.getClass());
//        System.arraycopy(elementData, 0, a, 0, size);
//        if (a.length > size)
//            a[size] = null;
//        return a;
//    }
//
//    // Positional Access Operations
//
//    @SuppressWarnings("unchecked")
//    E elementData(int index) {
//        return (E) elementData[index];
//    }
//
//    /**
//     * Returns the element at the specified position in this list.
//     *
//     * @param  index index of the element to return
//     * @return the element at the specified position in this list
//     * @throws IndexOutOfBoundsException {@inheritDoc}
//     */
//    public E get(int index) {
//        rangeCheck(index);
//
//        return elementData(index);
//    }
//
//    /**
//     * Replaces the element at the specified position in this list with
//     * the specified element.
//     *
//     * @param index index of the element to replace
//     * @param element element to be stored at the specified position
//     * @return the element previously at the specified position
//     * @throws IndexOutOfBoundsException {@inheritDoc}
//     */
//    public E set(int index, E element) {
//        rangeCheck(index);
//
//        E oldValue = elementData(index);
//        elementData[index] = element;
//        return oldValue;
//    }
//
//    /**
//     * Appends the specified element to the end of this list.
//     *
//     * @param e element to be appended to this list
//     * @return <tt>true</tt> (as specified by {@link Collection#add})
//     */
//    public boolean add(E e) {
//        ensureCapacityInternal(size + 1);  // Increments modCount!!
//        elementData[size++] = e;
//        return true;
//    }
//
//    /**
//     * Inserts the specified element at the specified position in this
//     * list. Shifts the element currently at that position (if any) and
//     * any subsequent elements to the right (adds one to their indices).
//     *
//     * @param index index at which the specified element is to be inserted
//     * @param element element to be inserted
//     * @throws IndexOutOfBoundsException {@inheritDoc}
//     */
//    public void add(int index, E element) {
//        rangeCheckForAdd(index);
//
//        ensureCapacityInternal(size + 1);  // Increments modCount!!
//        System.arraycopy(elementData, index, elementData, index + 1,
//                         size - index);
//        elementData[index] = element;
//        size++;
//    }
//
//    /**
//     * Removes the element at the specified position in this list.
//     * Shifts any subsequent elements to the left (subtracts one from their
//     * indices).
//     *
//     * @param index the index of the element to be removed
//     * @return the element that was removed from the list
//     * @throws IndexOutOfBoundsException {@inheritDoc}
//     */
//    public E remove(int index) {
//        rangeCheck(index);
//
//        modCount++;
//        E oldValue = elementData(index);
//
//        int numMoved = size - index - 1;
//        if (numMoved > 0)
//            System.arraycopy(elementData, index+1, elementData, index,
//                             numMoved);
//        elementData[--size] = null; // Let gc do its work
//
//        return oldValue;
//    }
//
//    /**
//     * Removes the first occurrence of the specified element from this list,
//     * if it is present.  If the list does not contain the element, it is
//     * unchanged.  More formally, removes the element with the lowest index
//     * <tt>i</tt> such that
//     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>
//     * (if such an element exists).  Returns <tt>true</tt> if this list
//     * contained the specified element (or equivalently, if this list
//     * changed as a result of the call).
//     *
//     * @param o element to be removed from this list, if present
//     * @return <tt>true</tt> if this list contained the specified element
//     */
//    public boolean remove(Object o) {
//        if (o == null) {
//            for (int index = 0; index < size; index++)
//                if (elementData[index] == null) {
//                    fastRemove(index);
//                    return true;
//                }
//        } else {
//            for (int index = 0; index < size; index++)
//                if (o.equals(elementData[index])) {
//                    fastRemove(index);
//                    return true;
//                }
//        }
//        return false;
//    }
//
//    /*
//     * Private remove method that skips bounds checking and does not
//     * return the value removed.
//     */
//    private void fastRemove(int index) {
//        modCount++;
//        int numMoved = size - index - 1;
//        if (numMoved > 0)
//            System.arraycopy(elementData, index+1, elementData, index,
//                             numMoved);
//        elementData[--size] = null; // Let gc do its work
//    }
//
//    /**
//     * Removes all of the elements from this list.  The list will
//     * be empty after this call returns.
//     */
//    public void clear() {
//        modCount++;
//
//        // Let gc do its work
//        for (int i = 0; i < size; i++)
//            elementData[i] = null;
//
//        size = 0;
//    }
//
//    /**
//     * Appends all of the elements in the specified collection to the end of
//     * this list, in the order that they are returned by the
//     * specified collection's Iterator.  The behavior of this operation is
//     * undefined if the specified collection is modified while the operation
//     * is in progress.  (This implies that the behavior of this call is
//     * undefined if the specified collection is this list, and this
//     * list is nonempty.)
//     *
//     * @param c collection containing elements to be added to this list
//     * @return <tt>true</tt> if this list changed as a result of the call
//     * @throws NullPointerException if the specified collection is null
//     */
//    public boolean addAll(Collection<? extends E> c) {
//        Object[] a = c.toArray();
//        int numNew = a.length;
//        ensureCapacityInternal(size + numNew);  // Increments modCount
//        System.arraycopy(a, 0, elementData, size, numNew);
//        size += numNew;
//        return numNew != 0;
//    }
//
//    /**
//     * Inserts all of the elements in the specified collection into this
//     * list, starting at the specified position.  Shifts the element
//     * currently at that position (if any) and any subsequent elements to
//     * the right (increases their indices).  The new elements will appear
//     * in the list in the order that they are returned by the
//     * specified collection's iterator.
//     *
//     * @param index index at which to insert the first element from the
//     *              specified collection
//     * @param c collection containing elements to be added to this list
//     * @return <tt>true</tt> if this list changed as a result of the call
//     * @throws IndexOutOfBoundsException {@inheritDoc}
//     * @throws NullPointerException if the specified collection is null
//     */
//    public boolean addAll(int index, Collection<? extends E> c) {
//        rangeCheckForAdd(index);
//
//        Object[] a = c.toArray();
//        int numNew = a.length;
//        ensureCapacityInternal(size + numNew);  // Increments modCount
//
//        int numMoved = size - index;
//        if (numMoved > 0)
//            System.arraycopy(elementData, index, elementData, index + numNew,
//                             numMoved);
//
//        System.arraycopy(a, 0, elementData, index, numNew);
//        size += numNew;
//        return numNew != 0;
//    }
//
//    /**
//     * Removes from this list all of the elements whose index is between
//     * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.
//     * Shifts any succeeding elements to the left (reduces their index).
//     * This call shortens the list by {@code (toIndex - fromIndex)} elements.
//     * (If {@code toIndex==fromIndex}, this operation has no effect.)
//     *
//     * @throws IndexOutOfBoundsException if {@code fromIndex} or
//     *         {@code toIndex} is out of range
//     *         ({@code fromIndex < 0 ||
//     *          fromIndex >= size() ||
//     *          toIndex > size() ||
//     *          toIndex < fromIndex})
//     */
//    protected void removeRange(int fromIndex, int toIndex) {
//        modCount++;
//        int numMoved = size - toIndex;
//        System.arraycopy(elementData, toIndex, elementData, fromIndex,
//                         numMoved);
//
//        // Let gc do its work
//        int newSize = size - (toIndex-fromIndex);
//        while (size != newSize)
//            elementData[--size] = null;
//    }
//
//    /**
//     * Checks if the given index is in range.  If not, throws an appropriate
//     * runtime exception.  This method does *not* check if the index is
//     * negative: It is always used immediately prior to an array access,
//     * which throws an ArrayIndexOutOfBoundsException if index is negative.
//     */
//    private void rangeCheck(int index) {
//        if (index >= size)
//            throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
//    }
//
//    /**
//     * A version of rangeCheck used by add and addAll.
//     */
//    private void rangeCheckForAdd(int index) {
//        if (index > size || index < 0)
//            throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
//    }
//
//    /**
//     * Constructs an IndexOutOfBoundsException detail message.
//     * Of the many possible refactorings of the error handling code,
//     * this "outlining" performs best with both server and client VMs.
//     */
//    private String outOfBoundsMsg(int index) {
//        return "Index: "+index+", Size: "+size;
//    }
//
//    /**
//     * Removes from this list all of its elements that are contained in the
//     * specified collection.
//     *
//     * @param c collection containing elements to be removed from this list
//     * @return {@code true} if this list changed as a result of the call
//     * @throws ClassCastException if the class of an element of this list
//     *         is incompatible with the specified collection
//     * (<a href="Collection.html#optional-restrictions">optional</a>)
//     * @throws NullPointerException if this list contains a null element and the
//     *         specified collection does not permit null elements
//     * (<a href="Collection.html#optional-restrictions">optional</a>),
//     *         or if the specified collection is null
//     * @see Collection#contains(Object)
//     */
//    public boolean removeAll(Collection<?> c) {
//        return batchRemove(c, false);
//    }
//
//    /**
//     * Retains only the elements in this list that are contained in the
//     * specified collection.  In other words, removes from this list all
//     * of its elements that are not contained in the specified collection.
//     *
//     * @param c collection containing elements to be retained in this list
//     * @return {@code true} if this list changed as a result of the call
//     * @throws ClassCastException if the class of an element of this list
//     *         is incompatible with the specified collection
//     * (<a href="Collection.html#optional-restrictions">optional</a>)
//     * @throws NullPointerException if this list contains a null element and the
//     *         specified collection does not permit null elements
//     * (<a href="Collection.html#optional-restrictions">optional</a>),
//     *         or if the specified collection is null
//     * @see Collection#contains(Object)
//     */
//    public boolean retainAll(Collection<?> c) {
//        return batchRemove(c, true);
//    }
//
//    private boolean batchRemove(Collection<?> c, boolean complement) {
//        final Object[] elementData = this.elementData;
//        int r = 0, w = 0;
//        boolean modified = false;
//        try {
//            for (; r < size; r++)
//                if (c.contains(elementData[r]) == complement)
//                    elementData[w++] = elementData[r];
//        } finally {
//            // Preserve behavioral compatibility with AbstractCollection,
//            // even if c.contains() throws.
//            if (r != size) {
//                System.arraycopy(elementData, r,
//                                 elementData, w,
//                                 size - r);
//                w += size - r;
//            }
//            if (w != size) {
//                for (int i = w; i < size; i++)
//                    elementData[i] = null;
//                modCount += size - w;
//                size = w;
//                modified = true;
//            }
//        }
//        return modified;
//    }
//
//    /**
//     * Save the state of the <tt>ArrayList</tt> instance to a stream (that
//     * is, serialize it).
//     *
//     * @serialData The length of the array backing the <tt>ArrayList</tt>
//     *             instance is emitted (int), followed by all of its elements
//     *             (each an <tt>Object</tt>) in the proper order.
//     */
//    private void writeObject(java.io.ObjectOutputStream s)
//        throws java.io.IOException{
//        // Write out element count, and any hidden stuff
//        int expectedModCount = modCount;
//        s.defaultWriteObject();
//
//        // Write out array length
//        s.writeInt(elementData.length);
//
//        // Write out all elements in the proper order.
//        for (int i=0; i<size; i++)
//            s.writeObject(elementData[i]);
//
//        if (modCount != expectedModCount) {
//            throw new ConcurrentModificationException();
//        }
//
//    }
//
//    /**
//     * Reconstitute the <tt>ArrayList</tt> instance from a stream (that is,
//     * deserialize it).
//     */
//    private void readObject(java.io.ObjectInputStream s)
//        throws java.io.IOException, ClassNotFoundException {
//        // Read in size, and any hidden stuff
//        s.defaultReadObject();
//
//        // Read in array length and allocate array
//        int arrayLength = s.readInt();
//        Object[] a = elementData = new Object[arrayLength];
//
//        // Read in all elements in the proper order.
//        for (int i=0; i<size; i++)
//            a[i] = s.readObject();
//    }
//
//    /**
//     * Returns a list iterator over the elements in this list (in proper
//     * sequence), starting at the specified position in the list.
//     * The specified index indicates the first element that would be
//     * returned by an initial call to {@link ListIterator#next next}.
//     * An initial call to {@link ListIterator#previous previous} would
//     * return the element with the specified index minus one.
//     *
//     * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
//     *
//     * @throws IndexOutOfBoundsException {@inheritDoc}
//     */
//    public ListIterator<E> listIterator(int index) {
//        if (index < 0 || index > size)
//            throw new IndexOutOfBoundsException("Index: "+index);
//        return new ListItr(index);
//    }
//
//    /**
//     * Returns a list iterator over the elements in this list (in proper
//     * sequence).
//     *
//     * <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
//     *
//     * @see #listIterator(int)
//     */
//    public ListIterator<E> listIterator() {
//        return new ListItr(0);
//    }
//
//    /**
//     * Returns an iterator over the elements in this list in proper sequence.
//     *
//     * <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
//     *
//     * @return an iterator over the elements in this list in proper sequence
//     */
//    public Iterator<E> iterator() {
//        return new Itr();
//    }
//
//    /**
//     * An optimized version of AbstractList.Itr
//     */
//    private class Itr implements Iterator<E> {
//        int cursor;       // index of next element to return
//        int lastRet = -1; // index of last element returned; -1 if no such
//        int expectedModCount = modCount;
//
//        public boolean hasNext() {
//            return cursor != size;
//        }
//
//        @SuppressWarnings("unchecked")
//        public E next() {
//            checkForComodification();
//            int i = cursor;
//            if (i >= size)
//                throw new NoSuchElementException();
//            Object[] elementData = ArrayList.this.elementData;
//            if (i >= elementData.length)
//                throw new ConcurrentModificationException();
//            cursor = i + 1;
//            return (E) elementData[lastRet = i];
//        }
//
//        public void remove() {
//            if (lastRet < 0)
//                throw new IllegalStateException();
//            checkForComodification();
//
//            try {
//                ArrayList.this.remove(lastRet);
//                cursor = lastRet;
//                lastRet = -1;
//                expectedModCount = modCount;
//            } catch (IndexOutOfBoundsException ex) {
//                throw new ConcurrentModificationException();
//            }
//        }
//
//        final void checkForComodification() {
//            if (modCount != expectedModCount)
//                throw new ConcurrentModificationException();
//        }
//    }
//
//    /**
//     * An optimized version of AbstractList.ListItr
//     */
//    private class ListItr extends Itr implements ListIterator<E> {
//        ListItr(int index) {
//            super();
//            cursor = index;
//        }
//
//        public boolean hasPrevious() {
//            return cursor != 0;
//        }
//
//        public int nextIndex() {
//            return cursor;
//        }
//
//        public int previousIndex() {
//            return cursor - 1;
//        }
//
//        @SuppressWarnings("unchecked")
//        public E previous() {
//            checkForComodification();
//            int i = cursor - 1;
//            if (i < 0)
//                throw new NoSuchElementException();
//            Object[] elementData = ArrayList.this.elementData;
//            if (i >= elementData.length)
//                throw new ConcurrentModificationException();
//            cursor = i;
//            return (E) elementData[lastRet = i];
//        }
//
//        public void set(E e) {
//            if (lastRet < 0)
//                throw new IllegalStateException();
//            checkForComodification();
//
//            try {
//                ArrayList.this.set(lastRet, e);
//            } catch (IndexOutOfBoundsException ex) {
//                throw new ConcurrentModificationException();
//            }
//        }
//
//        public void add(E e) {
//            checkForComodification();
//
//            try {
//                int i = cursor;
//                ArrayList.this.add(i, e);
//                cursor = i + 1;
//                lastRet = -1;
//                expectedModCount = modCount;
//            } catch (IndexOutOfBoundsException ex) {
//                throw new ConcurrentModificationException();
//            }
//        }
//    }
//
//    /**
//     * Returns a view of the portion of this list between the specified
//     * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.  (If
//     * {@code fromIndex} and {@code toIndex} are equal, the returned list is
//     * empty.)  The returned list is backed by this list, so non-structural
//     * changes in the returned list are reflected in this list, and vice-versa.
//     * The returned list supports all of the optional list operations.
//     *
//     * <p>This method eliminates the need for explicit range operations (of
//     * the sort that commonly exist for arrays).  Any operation that expects
//     * a list can be used as a range operation by passing a subList view
//     * instead of a whole list.  For example, the following idiom
//     * removes a range of elements from a list:
//     * <pre>
//     *      list.subList(from, to).clear();
//     * </pre>
//     * Similar idioms may be constructed for {@link #indexOf(Object)} and
//     * {@link #lastIndexOf(Object)}, and all of the algorithms in the
//     * {@link Collections} class can be applied to a subList.
//     *
//     * <p>The semantics of the list returned by this method become undefined if
//     * the backing list (i.e., this list) is <i>structurally modified</i> in
//     * any way other than via the returned list.  (Structural modifications are
//     * those that change the size of this list, or otherwise perturb it in such
//     * a fashion that iterations in progress may yield incorrect results.)
//     *
//     * @throws IndexOutOfBoundsException {@inheritDoc}
//     * @throws IllegalArgumentException {@inheritDoc}
//     */
//    public List<E> subList(int fromIndex, int toIndex) {
//        subListRangeCheck(fromIndex, toIndex, size);
//        return new SubList(this, 0, fromIndex, toIndex);
//    }
//
//    static void subListRangeCheck(int fromIndex, int toIndex, int size) {
//        if (fromIndex < 0)
//            throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
//        if (toIndex > size)
//            throw new IndexOutOfBoundsException("toIndex = " + toIndex);
//        if (fromIndex > toIndex)
//            throw new IllegalArgumentException("fromIndex(" + fromIndex +
//                                               ") > toIndex(" + toIndex + ")");
//    }
//
//    private class SubList extends AbstractList<E> implements RandomAccess {
//        private final AbstractList<E> parent;
//        private final int parentOffset;
//        private final int offset;
//        int size;
//
//        SubList(AbstractList<E> parent,
//                int offset, int fromIndex, int toIndex) {
//            this.parent = parent;
//            this.parentOffset = fromIndex;
//            this.offset = offset + fromIndex;
//            this.size = toIndex - fromIndex;
//            this.modCount = ArrayList.this.modCount;
//        }
//
//        public E set(int index, E e) {
//            rangeCheck(index);
//            checkForComodification();
//            E oldValue = ArrayList.this.elementData(offset + index);
//            ArrayList.this.elementData[offset + index] = e;
//            return oldValue;
//        }
//
//        public E get(int index) {
//            rangeCheck(index);
//            checkForComodification();
//            return ArrayList.this.elementData(offset + index);
//        }
//
//        public int size() {
//            checkForComodification();
//            return this.size;
//        }
//
//        public void add(int index, E e) {
//            rangeCheckForAdd(index);
//            checkForComodification();
//            parent.add(parentOffset + index, e);
//            this.modCount = parent.modCount;
//            this.size++;
//        }
//
//        public E remove(int index) {
//            rangeCheck(index);
//            checkForComodification();
//            E result = parent.remove(parentOffset + index);
//            this.modCount = parent.modCount;
//            this.size--;
//            return result;
//        }
//
//        protected void removeRange(int fromIndex, int toIndex) {
//            checkForComodification();
//            parent.removeRange(parentOffset + fromIndex,
//                               parentOffset + toIndex);
//            this.modCount = parent.modCount;
//            this.size -= toIndex - fromIndex;
//        }
//
//        public boolean addAll(Collection<? extends E> c) {
//            return addAll(this.size, c);
//        }
//
//        public boolean addAll(int index, Collection<? extends E> c) {
//            rangeCheckForAdd(index);
//            int cSize = c.size();
//            if (cSize==0)
//                return false;
//
//            checkForComodification();
//            parent.addAll(parentOffset + index, c);
//            this.modCount = parent.modCount;
//            this.size += cSize;
//            return true;
//        }
//
//        public Iterator<E> iterator() {
//            return listIterator();
//        }
//
//        public ListIterator<E> listIterator(final int index) {
//            checkForComodification();
//            rangeCheckForAdd(index);
//            final int offset = this.offset;
//
//            return new ListIterator<E>() {
//                int cursor = index;
//                int lastRet = -1;
//                int expectedModCount = ArrayList.this.modCount;
//
//                public boolean hasNext() {
//                    return cursor != SubList.this.size;
//                }
//
//                @SuppressWarnings("unchecked")
//                public E next() {
//                    checkForComodification();
//                    int i = cursor;
//                    if (i >= SubList.this.size)
//                        throw new NoSuchElementException();
//                    Object[] elementData = ArrayList.this.elementData;
//                    if (offset + i >= elementData.length)
//                        throw new ConcurrentModificationException();
//                    cursor = i + 1;
//                    return (E) elementData[offset + (lastRet = i)];
//                }
//
//                public boolean hasPrevious() {
//                    return cursor != 0;
//                }
//
//                @SuppressWarnings("unchecked")
//                public E previous() {
//                    checkForComodification();
//                    int i = cursor - 1;
//                    if (i < 0)
//                        throw new NoSuchElementException();
//                    Object[] elementData = ArrayList.this.elementData;
//                    if (offset + i >= elementData.length)
//                        throw new ConcurrentModificationException();
//                    cursor = i;
//                    return (E) elementData[offset + (lastRet = i)];
//                }
//
//                public int nextIndex() {
//                    return cursor;
//                }
//
//                public int previousIndex() {
//                    return cursor - 1;
//                }
//
//                public void remove() {
//                    if (lastRet < 0)
//                        throw new IllegalStateException();
//                    checkForComodification();
//
//                    try {
//                        SubList.this.remove(lastRet);
//                        cursor = lastRet;
//                        lastRet = -1;
//                        expectedModCount = ArrayList.this.modCount;
//                    } catch (IndexOutOfBoundsException ex) {
//                        throw new ConcurrentModificationException();
//                    }
//                }
//
//                public void set(E e) {
//                    if (lastRet < 0)
//                        throw new IllegalStateException();
//                    checkForComodification();
//
//                    try {
//                        ArrayList.this.set(offset + lastRet, e);
//                    } catch (IndexOutOfBoundsException ex) {
//                        throw new ConcurrentModificationException();
//                    }
//                }
//
//                public void add(E e) {
//                    checkForComodification();
//
//                    try {
//                        int i = cursor;
//                        SubList.this.add(i, e);
//                        cursor = i + 1;
//                        lastRet = -1;
//                        expectedModCount = ArrayList.this.modCount;
//                    } catch (IndexOutOfBoundsException ex) {
//                        throw new ConcurrentModificationException();
//                    }
//                }
//
//                final void checkForComodification() {
//                    if (expectedModCount != ArrayList.this.modCount)
//                        throw new ConcurrentModificationException();
//                }
//            };
//        }
//
//        public List<E> subList(int fromIndex, int toIndex) {
//            subListRangeCheck(fromIndex, toIndex, size);
//            return new SubList(this, offset, fromIndex, toIndex);
//        }
//
//        private void rangeCheck(int index) {
//            if (index < 0 || index >= this.size)
//                throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
//        }
//
//        private void rangeCheckForAdd(int index) {
//            if (index < 0 || index > this.size)
//                throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
//        }
//
//        private String outOfBoundsMsg(int index) {
//            return "Index: "+index+", Size: "+this.size;
//        }
//
//        private void checkForComodification() {
//            if (ArrayList.this.modCount != this.modCount)
//                throw new ConcurrentModificationException();
//        }
//    }
//}
